After this discovery, the Kepler-90 solar system has come at par with our own in terms of number of planets revolving around a single star, said NASA. How did Google AI achieve this feat?

The computers were coded to identify planets by analysing data from Kepler, in which the telescope had previously recorded signals from exoplanets. Applying this process, researchers Christopher Shallue and Andrew Vanderburg trained a computer to identify Kepler's light readings, that is the minute changes in brightness that are caused by a planet passing in front of a star. This process has been inspired by how neurons connect in human brains and transmit signals.

This man-made neural network worked tirelessly by sifting through tons of Kepler data, finally finding weak transit signals that indicated the possibility of a yet-undiscovered eighth planet in the constellation Draco.

"In my spare time, I started googling for 'finding exoplanets with large data sets' and found out about the Kepler mission and the huge data set available," said Shallue, who is a senior software engineer with the Google AI research team.

After the neural network was trained manually to identify passing exoplanets by analyzing 15,000 signals from the Kepler catalogue, it started giving correct results for true planets and false positives in 96 percent of cases. This system was then utilized to search for the weaker signals in 670 star systems in which exoplanets had been previously discovered as they had the best chance of containing more celestial bodies.

"We got lots of false positives of planets, but also potentially more real planets," said Vanderburg. He also compared the finding of exoplanets to sifting through rocks with a fine sieve to find jewels.

The eighth planet in the Kepler-90 system has been named Kepler-90i. However, this exoplanet has been termed uninhabitable as it is small in size, hot and quite rocky. Nonetheless, NASA is now hopeful that more such celestial bodies and space objects may now be discovered with the help of artificial intelligence.